Flash: how can I cast a slider class to DisplayObject in Flash?

I tried this:

    (DisplayObject(slider)).parent.addEventListener(CustomEvent.CUSTOM_EVENT_TYPE, onCustomEventType);

but开发者_运维问答 flash doesn't like

For whole context see Is it impossible with Flash to get the Instance Creator?

(slider as DisplayObject).parent.addEventListener(CustomEvent.CUSTOM_EVENT_TYPE, onCustomEventType);